Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Dielectric materials are commonly used in energy storage devices, e.g., to separate opposing electrodes in an electrostatic capacitor. Nanocomposite dielectric materials include inorganic nanoparticles in a polymer base, which together have relatively high dielectric constants due in part to the inorganic nanoparticles while retaining much of the processibility advantages of the base polymer. For energy storage applications, such as electrostatic capacitors, a high breakdown strength and good endurance may be desirable so that large charge densities may be tolerated over the device life.
The present disclosure appreciates that there are several limitations with known nanocomposite dielectrics. For example, nanocomposite dielectrics have been described as having less than desirable breakdown strength, since it is believed that the presence of high permittivity nanoparticles may lead to highly inhomogenous internal electric fields, creating local hot spots inside the composite where the actual fields may be much higher than the applied field. The hot spots may lead to breakdown of the nanocomposite dielectric, limiting performance and lifetime. Thus, implementing dielectric materials with desirable properties, particularly nanocomposite dielectric materials for use in in energy storage devices, can be a complex undertaking.